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/* MCP23017 - drive the Microchip MCP23017 16-bit Port Extender using I2C
* Copyright (c) 2010 Wim Huiskamp, Romilly Cocking (original version for SPI)
*
* Released under the MIT License: http://mbed.org/license/mit
*
* version 0.2
*/

#include "mbed.h"
#include "MCP23017.h"

MCP23017::MCP23017(I2C &i2c, char deviceAddress) : _i2c(i2c) {
    _writeOpcode = deviceAddress & 0xFE; // low order bit = 0 for write
    _readOpcode  = deviceAddress | 0x01; // low order bit = 1 for read
    _init();
}

char MCP23017::_read(char address) {
    char data[2];
    char result;

    data[0] = address;
    _i2c.write(_writeOpcode, data, 1);      // Select Register for reading
    result = _i2c.read(_readOpcode);        // Read from selected Register
    
    return result;
}


void MCP23017::_write(char address, char byte) {
    char data[2];

    data[0] = address;
    data[1] = byte;
    _i2c.write(_writeOpcode, data, 2);    // Write data to selected Register
}


void MCP23017::_init() {
    _write(IOCON, (IOCON_BYTE_MODE | IOCON_HAEN )); // Hardware addressing on, operations toggle between A and B registers

}

void MCP23017::direction(Port port, char direction) {
    _write(port + IODIRA, direction);
}

void MCP23017::configurePullUps(Port port, char offOrOn) {
    _write(port + GPPUA, offOrOn);
}

void MCP23017::interruptEnable(Port port, char interruptsEnabledMask) {
    _write(port + GPINTENA, interruptsEnabledMask);
}

void MCP23017::mirrorInterrupts(bool mirror) {
 char iocon = _read(IOCON);
    if (mirror) {
        iocon = iocon | INTERRUPT_MIRROR_BIT;
    } else {
        iocon = iocon & ~INTERRUPT_MIRROR_BIT;
    }
    _write(IOCON, iocon);

}

void  MCP23017::interruptPolarity(Polarity polarity) {
    char iocon = _read(IOCON);
    if (polarity == ACTIVE_LOW) {
        iocon = iocon & ~INTERRUPT_POLARITY_BIT;
    } else {
        iocon = iocon | INTERRUPT_POLARITY_BIT;
    }
    _write(IOCON, iocon);
}

void MCP23017::defaultValue(Port port, char valuesToCompare) {
    _write(port + DEFVALA, valuesToCompare);
}

void MCP23017::interruptControl(Port port, char interruptControlBits) {
    _write(port + INTCONA, interruptControlBits);
}

void MCP23017::write(Port port, char byte) {
    _write(port + OLATA, byte);
    
//faster    (56 sec for lcd init)
//   char data[2];
//
//   data[0] = OLATA + port;
//   data[1] = byte;
//   _i2c.write(_writeOpcode, data, 2);    // Write data to selected Register

//faster  47 sec for complete init
//   _i2c.start();
//   _i2c.write(_writeOpcode);    // Select Device
//   _i2c.write(OLATA + port);    // Select Register
//   _i2c.write(byte);            // Write data to selected Register
//   _i2c.stop();  
}
    

char MCP23017::read(Port port) {
    return _read(port + GPIOA);
}

// Optimised Databus write operation for Graphics LCD.
//   Port A is used as databus, Port B is used as controlbus.
//
void MCP23017::databus_write(char data, char ctrl_1, char ctrl_2, char ctrl_3, char ctrl_4) {

   _i2c.start();
   _i2c.write(_writeOpcode);    // Select Device
   _i2c.write(OLATA);           // Select Register A

//Remove separate CS Low, to speed up
//   _i2c.write(data);            // Write data to Port A Register and Auto-incr to Register B
//   _i2c.write(ctrl_1);          // Write control to Port B  and Auto-incr to Register A
   
   _i2c.write(data);            // Write data to Port A Register and Auto-incr to Register B
   _i2c.write(ctrl_2);          // Write control to Port B  and Auto-incr to Register A
   
   _i2c.write(data);            // Write data to Port A Register and Auto-incr to Register B
   _i2c.write(ctrl_3);          // Write control to Port B  and Auto-incr to Register A

//Remove separate CS High, to speed up
//   _i2c.write(data);            // Write data to Port A Register and Auto-incr to Register B
//   _i2c.write(ctrl_4);          // Write control to Port B  and Auto-incr to Register A
   
   _i2c.stop();  
}